The reality of Darrelle Revis’ knee injury has sunk in to such an extent that coach Rex Ryan is using it as motivational tool, saying there is a fraction of a chance that Revis could return, if the Jets make it to the Super Bowl.

Don’t believe it, but at least New Rex didn’t guarantee on Friday that Revis would be back, or guarantee his Jets would be playing in Super Bowl XLVII in New Orleans.

“I’m not guaranteeing it’s going to happen by any stretch,’’ Ryan said of such a miraculous Revis return from a torn ligament in his left knee.

This is all Rex’s way of telling his team they can get to the playoffs without Revis. With the mighty 49ers in town, this is Step-Up Sunday for the Jets.

It’s interesting to note that Tebow Mania has subsided a bit. In fact, after Friday’s practice, about half the reporters were talking to defensive backs coach Dennis Thurman while Tebow was providing his usual end-of-the-week press conference.

Add that tight end Dustin Keller (hamstring) is expected to return and that not one disgruntled Jet got into it with any media members on Friday, like Bart Scott did last week, and you might even say that the Jets are showing a sense of purpose.

They better have it all together today or they are going to get drilled by the 49ers — a talented, angry squad that comes to MetLife Stadium after spending a week in gritty Youngstown, Ohio, to put them in the football mood.

While choreographing his Revis “news,’’ Ryan pointed out the Jets had a great week of practice. Such is the case after a superstar goes down. It is much like how the Yankees had to come together after Mariano Rivera blew out his knee. When a uniquely talented player is lost, others have to step up, knowing it must take a team effort to carry the them home.

Ryan said the Jets’ sense of purpose this week is deeper than just trying to pick up the Revis Pieces.

“Anytime you play against a tremendous football team there’s that challenge, and as a competitor, you know you have to step your game up,’’ he said. “Obviously having to overcome [the loss] of a tremendous player, that may add to it a little bit. The fact that you are in first place may add something to it as well. All of those things combined, and the fact we’re playing at home, we don’t want to disappoint our fans. So there are a lot of things that go into it, probably the number one thing is that we just want to win.’’

The Jets are fortunate to be 2-1. They will have their hands full with the unique weapon that is Vernon Davis. Ryan pointed to one play that makes Davis, who has a bit of a back issue, such a fearsome tight end.

“Woo, he can run,’’ Ryan said. “They do some different things with him at tight end that no team in the league does. … They’ll put him as a backside tight end and that will release him straight down the field, not straight down the field, but you know how our fields have that red line. They’ll put him on that red line and just throw it up to him. No other team can do that, but he’s so fast even from an end line position he can get out there. It’s challenging to say the least.’’

Thurman knows the challenge ahead for his defensive backs. He believes Kyle Wilson & Co. will step up. It’s time for his young DBs to trash their “pacifiers,’’ he noted, before adding, “It’s time for them to eat meat.’’

The Jets are again talking a good game. Let’s see if they can play one. Welcome to Step-Up Sunday.